1. Field
One or more embodiments of the present invention relate to a method of producing L-amino acids by using a gene transcription inhibition method.
2. Description of the Related Art
Pyruvate, which is produced through glycolysis of various carbon sources in coryneform microorganisms, is converted into aspartate via oxaloacetate. The aspartate is converted into amino acids such as threonine, methionine, isoleucine, and lysine through various biosynthetic pathways (FIG. 1). Therefore, the expression of genes, located at each branch point in the amino acid biosynthetic processes, may be inhibited to decrease byproduct production and increase target amino acid production.
As described above, to develop a microorganism strain, which is capable of high-potency production of target materials by using genetic engineering and metabolic engineering, the expression of genes related with various metabolic processes of a microorganism needs to be selectively controlled. Recently, a technology for weakening gene expression, which is called “artificial convergent transcription,” was reported (Krylov et al., J Mol Microbiol Biotechnol, 18:1-13, 2010). The artificial convergent transcription is a technology for weakening the expression of a target gene by inserting a promoter into a downstream region of a transcription terminator of the target gene so that the opposite direction of the promoter causes a collision of RNA polymerase complexes derived from each promoter during transcription.
The inventors developed a technology to selectively inhibit the expression of a target gene in the presence of acetate by inserting an acetate-inducible promoter in a direction opposite to the target gene transcription, and effectively applied the technology to inhibit the expression of genes located at branch points in a coryneform microorganism. Then the inventors verified to provide the coryneform microorganism of producing L-amino acid with high yield by using the technology and completed the present invention.